1. Field of the Invention
The present invention relates to a rotation angle detecting device that detects a rotation angle of an rotating object.
2. Description of the Related Art
Usually, a rotation angle of a rotating object is detected by a rotation angle detecting device that is constituted of a permanent magnet rotor linked with the rotating object, a pair of magnetic sensing elements that are respectively disposed around the permanent magnet rotor to be spaced apart from each other in the rotating direction, as disclosed in JP-A-2004-271495 or, its counterpart, US 2004/0164733 A1. When the rotating object rotates, the magnetic sensing elements detect a change in a magnetic field that is generated by the permanent magnet rotor, thereby providing signals relating to the rotation angle of the rotation object.
Because the magnetic sensing elements are spaced apart in the rotating direction, it is difficult to accurately position the magnetic sensing elements. In other words, the angle formed between two magnetic sensing elements may not be a desired angle, the setting directions of two magnetic sensing elements may not be desired directions, or temperature difference between two magnetic sensing elements may arise. As a result, the magnetic sensing elements may generate signals that may cause an error in the rotation angle to be detected.